// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_BASE_TEST_COMPLETION_CALLBACK_H_
#define NET_BASE_TEST_COMPLETION_CALLBACK_H_

#include <stdint.h>

#include <memory>

#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/macros.h"
#include "net/base/completion_callback.h"
#include "net/base/net_errors.h"

//-----------------------------------------------------------------------------
// completion callback helper

// A helper class for completion callbacks, designed to make it easy to run
// tests involving asynchronous operations.  Just call WaitForResult to wait
// for the asynchronous operation to complete.  Uses a RunLoop to spin the
// current MessageLoop while waiting.  The callback must be invoked on the same
// thread WaitForResult is called on.
//
// NOTE: Since this runs a message loop to wait for the completion callback,
// there could be other side-effects resulting from WaitForResult.  For this
// reason, this class is probably not ideal for a general application.
//
namespace base {
class RunLoop;
}

namespace net {

class IOBuffer;

namespace internal {

    class TestCompletionCallbackBaseInternal {
    public:
        bool have_result() const { return have_result_; }

    protected:
        TestCompletionCallbackBaseInternal();
        virtual ~TestCompletionCallbackBaseInternal();

        void DidSetResult();
        void WaitForResult();

    private:
        // RunLoop.  Only non-NULL during the call to WaitForResult, so the class is
        // reusable.
        std::unique_ptr<base::RunLoop> run_loop_;
        bool have_result_;

        DISALLOW_COPY_AND_ASSIGN(TestCompletionCallbackBaseInternal);
    };

    template <typename R>
    class TestCompletionCallbackTemplate
        : public TestCompletionCallbackBaseInternal {
    public:
        virtual ~TestCompletionCallbackTemplate() override { }

        R WaitForResult()
        {
            TestCompletionCallbackBaseInternal::WaitForResult();
            return result_;
        }

        R GetResult(R result)
        {
            if (ERR_IO_PENDING != result)
                return result;
            return WaitForResult();
        }

    protected:
        TestCompletionCallbackTemplate()
            : result_(R())
        {
        }

        // Override this method to gain control as the callback is running.
        virtual void SetResult(R result)
        {
            result_ = result;
            DidSetResult();
        }

    private:
        R result_;

        DISALLOW_COPY_AND_ASSIGN(TestCompletionCallbackTemplate);
    };

} // namespace internal

class TestClosure : public internal::TestCompletionCallbackBaseInternal {
public:
    using internal::TestCompletionCallbackBaseInternal::WaitForResult;

    TestClosure();
    ~TestClosure() override;

    const base::Closure& closure() const { return closure_; }

private:
    const base::Closure closure_;

    DISALLOW_COPY_AND_ASSIGN(TestClosure);
};

// Base class overridden by custom implementations of TestCompletionCallback.
typedef internal::TestCompletionCallbackTemplate<int>
    TestCompletionCallbackBase;

typedef internal::TestCompletionCallbackTemplate<int64_t>
    TestInt64CompletionCallbackBase;

class TestCompletionCallback : public TestCompletionCallbackBase {
public:
    TestCompletionCallback();
    ~TestCompletionCallback() override;

    const CompletionCallback& callback() const { return callback_; }

private:
    const CompletionCallback callback_;

    DISALLOW_COPY_AND_ASSIGN(TestCompletionCallback);
};

class TestInt64CompletionCallback : public TestInt64CompletionCallbackBase {
public:
    TestInt64CompletionCallback();
    ~TestInt64CompletionCallback() override;

    const Int64CompletionCallback& callback() const { return callback_; }

private:
    const Int64CompletionCallback callback_;

    DISALLOW_COPY_AND_ASSIGN(TestInt64CompletionCallback);
};

// Makes sure that the buffer is not referenced when the callback runs.
class ReleaseBufferCompletionCallback : public TestCompletionCallback {
public:
    explicit ReleaseBufferCompletionCallback(IOBuffer* buffer);
    ~ReleaseBufferCompletionCallback() override;

private:
    void SetResult(int result) override;

    IOBuffer* buffer_;
    DISALLOW_COPY_AND_ASSIGN(ReleaseBufferCompletionCallback);
};

} // namespace net

#endif // NET_BASE_TEST_COMPLETION_CALLBACK_H_
